Patrones de reclutamiento en cuatro especies de Physaria (Brassicaceae): implicancias para el mantenimiento de la densidad en poblaciones silvestres y en cultivo

En zonas áridas, el reclutamiento de nuevos individuos es un proceso crítico que determina la viabilidad poblacional, el potencial de invasión de plantas alóctonas y el éxito en el establecimiento de cultivos. Se evaluaron las principales etapas del reclutamiento (lluvia de semillas, fecha de emergencia y supervivencia de las plántulas) en cuatro especies de Physaria (P. gracilis, P. angustifolia, P. pinetorum, y P. mendocina) en un experimento a campo en la Patagonia argentina, con el objetivo evaluar el potencial de este proceso para entender la dinámica poblacional y su utilidad como una alternativa sustentable de restablecimiento del cultivo. Se estudió el efecto de la disponibilidad de agua y de la densidad inicial de plántulas sobre la densidad final del cultivo. La cantidad total de semillas dispersadas fue mayor en P. gracilis y P. pinetorum que en las otras especies. No hubo germinación en P. mendocina. Las semillas de P. pinetorum germinaron a fines del verano, mientras que el resto de las especies germinó en primavera. La supervivencia estuvo modulada por un mecanismo denso-dependiente. En P. pinetorum, la densidad de plántulas fue estable en el tiempo en las parcelas de baja densidad inicial, mientras que decreció en las parcelas de densidades media y alta. A pesar de esto, la densidad final fue mayor en las parcelas de alta densidad inicial. La densidad final de P. gracilis respondió a la frecuencia de riego. Concluimos que la cantidad de semillas es adecuada para el restablecimiento de la población en las cuatro especies, aunque los procesos que resultan en la densidad final fueron dependientes de la especie. El control apropiado de la densidad inicial de plántulas jugaría un rol relevante para que el restablecimiento se produzca a densidades apropiadas para el cultivo en P. pinetorum.Seedling recruitment is a critical stage of a plant's cycle which determines population viability, the potential for invasiveness of a plant species and the success of establishment of a crop, among other processes. We evaluated the most relevant stages leading to recruitment (seed-rain, the time of seedling emergence, and seedling survival) in four species of Physaria (P. gracilis, P. angustifolia, Physaria pinetorum and P. mendocina) in a field experiment in Patagonia, Argentina, to assess the possibility of using spontaneous recruitment to understand population dynamics and to evaluate the potential of this process as a tool for crop reestablishment. We determined the effect of water availability and initial seedling density on final stand density. The total amount of dispersed seed was higher in P. gracilis and P. pinetorum than in the other two species. Physariapinetorum germinated in late summer, while P. angustifolia and P. gracilis germinatedin spring. No germination was registered for P. mendocina. In the three species whose seeds germinated, seedling survival was modulated by a density-dependent mechanism. For P. pinetorum seedling density was stable over time in low-density plots, while it decreased in high- and medium-density plots. Still, the highest final density was found in those plots with high initial density. Final density of P. gracilis also responded to irrigation treatment. The amount of dispersed seeds was adequate for the re-establishment of the crop in all four species, although the following stages were species-dependent. An appropriate control of seedling density at the initial stage of crop establishment may play a relevant role in the proper regeneration of the crop.Fil: González Paleo, Luciana. Museo Paleontológico Egidio Feruglio; Argentina. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pastor Pastor, Alejandro. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Bar Lamas, Marlene Ivonne. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vilela, Alejandra Elena. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ravetta, Damián Andrés. Museo Paleontológico Egidio Feruglio; Argentina. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Lidocaine effects on acetylcholine-elicited currents from mouse superior cervical ganglion neurons

Lidocaine is a commonly used local anaesthetic that, besides blocking voltage-dependent Na+ channels, has multiple inhibitory effects on muscle-type nicotinic acetylcholine (ACh) receptors (nAChRs). In the present study, we have investigated the effects of lidocaine on ACh-elicited currents (IAChs) from cultured mouse superior cervical ganglion (SCG) neurons, which mainly express heteromeric α3β4 nAChRs. Neurons were voltage-clamped by using the perforated-patch method and IAChs were elicited by fast application of ACh (100-300 μM), either alone or in presence of lidocaine at different concentrations. IAChs were reversibly blocked by lidocaine in a concentration-dependent way (IC50 = 41 μM; nH close to 1) and the inhibition was, at least partially, voltage-dependent, indicating an open-channel blockade. Besides, lidocaine blocked resting (closed) nAChRs, as evidenced by the increased inhibition caused by a 12 s lidocaine application just before its co-application with the agonist, and also enhanced IAChs desensitisation, at concentrations close to the IC50. These results indicate that lidocaine has diverse inhibitory actions on neuronal heteromeric nAChRs resembling those previously reported for Torpedo (muscle-type) nAChRs ( Alberola-Die et al., 2011). The similarity of lidocaine actions on different subtypes of heteromeric nAChRs differs with the specific effects of other compounds, restricted to particular subtypes of nAChRs.This work was supported by the following MICINN (Spanish government) grants: CONSOLIDER-INGENIO 2010 (CSD2008-00005), BFU2011-25371 and BFU2012-31359

Automated production of synthetic point clouds of truss bridges for semantic and instance segmentation using deep learning models

The cost of obtaining large volumes of bridge data with technologies like laser scanners hinders the training of deep learning models. To address this, this paper introduces a new method for creating synthetic point clouds of truss bridges and demonstrates the effectiveness of a deep learning approach for semantic and instance segmentation of these point clouds. The method generates point clouds by specifying the dimensions and components of the bridge, resulting in high variability in the generated dataset. A deep learning model is trained using the generated point clouds, which is an adapted version of JSNet. The accuracy of the results surpasses previous heuristic methods. The proposed methodology has significant implications for the development of automated inspection and monitoring systems for truss bridges. Furthermore, the success of the deep learning approach suggests its potential for semantic and instance segmentation of complex point clouds beyond truss bridges.Agencia Estatal de Investigación | Ref. PID2021-124236OB-C33Agencia Estatal de Investigación | Ref. RYC2021-033560-IUniversidade de Vigo/CISU

Instance and semantic segmentation of point clouds of large metallic truss bridges

Several methods have been developed for the semantic segmentation of reinforced concrete bridges, however, there is a gap for truss bridges. Therefore, in this study a state-of-the-art methodology for the instance and semantic segmentation of point clouds of truss bridges for modelling purposes is presented, which, to the best of the authors' knowledge, is the first such methodology. This algorithm segments each truss element and classifies them as a chord, diagonal, vertical post, interior lateral brace, bottom lateral brace, or strut. The algorithm consists of a sequence of methods, including principal component analysis or clustering, that analyse each point and its neighbours in the point cloud. Case studies show that by adjusting only six manually measured parameters, the algorithm can automatically segment a truss bridge point cloud.Agencia Estatal de Investigación | Ref. PID2021-124236OB-C3Agencia Estatal de Investigación | Ref. RYC2021–033560-IUniversidade de Vigo/CISU

Generating IFC-compliant models and structural graphs of truss bridges from dense point clouds

The IFC schema has been evolving towards the infrastructure domain. Furthermore, the use of laser scanning technologies as means to digitalize and monitor infrastructures has also significantly increased. This work presents an automated modelling approach for truss bridges that utilizes laser scanning data as its source for geometrical information. The methodology takes a partially instance-segmented point cloud of a truss bridge and generates both an IFC-compliant information model of the truss and the corresponding structural graph. This process uses bounding boxes and their collisions to overcome the missing data from the partial segmentation to create the truss model, as well as to identify the nodes that connect the different truss members. The methodology was tested on a use case made of 272 members and obtained the truss model and structural graph files.Universidade de Vigo | Ref. PREUVIGO-21Agencia Estatal de Investigación | Ref. FJC2020–046370-IAgencia Estatal de Investigación | Ref. PID2021-124236OB-C33Agencia Estatal de Investigación | Ref. FJC2020–046370-IFinanciado para publicación en acceso aberto: Universidade de Vigo/CISU